Operational Control weakness is what Malabo is referring too. The 139 overweight issue was directly due to the fact that they screwed up their W&B and never caught it. He isn't saying the 139 has weak controls.
They flew the 139's overweight for a number of weeks before the "anomaly" with the weight and balance was found and the aircraft were grounded pending Leonardo prescribing inspections for returning the aircraft to service.